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(11) | EP 1 447 774 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Method and apparatus for sampling on a non-power-of-two pixel grid |
| (57) The embodiments of the present invention are a method to perform anti-aliasing using
multi-sampling on a non-power-of-two pixel grid. Using the present invention with
6 sample multisampling gives the same visual antialiasing quality as 8 samples using
a prior art technique but uses less memory. A non-power-of-two equally spaced sample
from a conventional grid of size NxN, where N is 12 can be chosen using the present
invention. A scan conversion to determine the set of pixels covered by a polygon is
performed in two parts. According to one embodiment, the present invention can multiply
and divide by "N" in order to multisample an image using samples per pixel chosen
from a NxN sub-sample grid, where "N" is not necessarily a power of 2. The present
invention performs the divide by "N" step, where the step is achieved using a quick
divide by 3 or 12 technique.
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